The present invention concerns a novel system for communicating with a tank circuit that is implanted in a patient, for example, a telemetry system for communicating with an implanted cardiac pacer.
In cardiac pacing there is typically communication between the implanted pacer and an external telemetry/programming unit. The external telemetry/programming unit generally comprises a console which contains appropriate circuitry and operator controls for communicating with the implanted pacer. In its telemetry mode, signals from the pacer are received by the circuitry within the external console and are detected. In its programming mode, signals are transmitted from the circuitry within the console and are received by the circuitry within the implant and are stored. The external console is typically a relatively large unit which may have a width of about 5 inches, a length of about 10 inches and a weight of about 5 pounds.
An example of one type of telemetry console, and its operation in communicating with an implanted cardiac pacer, is disclosed in U.S. Pat. No. 4,361,153, issued Nov. 30, 1982. It can be seen that the external console is placed on the patient's skin, overlying the implant, in as close proximity as possible to the implant. Because of the bulkiness and weight of the external console, the patient is generally required to lie down during the telemetry or programming procedure.
We have discovered a system for communicating with an implant in which the item in contact with the patient's skin and in proximity with the implant is extremely lightweight and small, thereby avoiding the difficulties concomitant with a bulky circuit console. Using the illustrative embodiment of our invention, the item which contacts the patient's skin externally can be manufactured with ease and economy, may be made sterilizable, may be disposable, may be flexible, may be constructed so that the patient may wear it for a period of time, and it affords a significant amount of latitude with respect to its placement on the patient.
Other objects and advantages of the present invention will become apparent as the description proceeds.